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Data Fields
snd_pcm_ioplug_callback_t Struct Reference
External PCM plugin SDK » External I/O plugin SDK

`#include <pcm_ioplug.h>`

## Data Fields
int(* | start )(snd_pcm_ioplug_t *io)
int(* | stop )(snd_pcm_ioplug_t *io)
snd_pcm_sframes_t(* | pointer )(snd_pcm_ioplug_t *io)
snd_pcm_sframes_t(* | transfer )(snd_pcm_ioplug_t *io, const snd_pcm_channel_area_t *areas, snd_pcm_uframes_t offset, snd_pcm_uframes_t size)
int(* | close )(snd_pcm_ioplug_t *io)
int(* | hw_params )(snd_pcm_ioplug_t *io, snd_pcm_hw_params_t *params)
int(* | hw_free )(snd_pcm_ioplug_t *io)
int(* | sw_params )(snd_pcm_ioplug_t *io, snd_pcm_sw_params_t *params)
int(* | prepare )(snd_pcm_ioplug_t *io)
int(* | drain )(snd_pcm_ioplug_t *io)
int(* | pause )(snd_pcm_ioplug_t *io, int enable)
int(* | resume )(snd_pcm_ioplug_t *io)
int(* | poll_descriptors_count )(snd_pcm_ioplug_t *io)
int(* | poll_descriptors )(snd_pcm_ioplug_t *io, struct pollfd *pfd, unsigned int space)
int(* | poll_revents )(snd_pcm_ioplug_t *io, struct pollfd *pfd, unsigned int nfds, unsigned short *revents)
void(* | dump )(snd_pcm_ioplug_t *io, snd_output_t *out)
int(* | delay )(snd_pcm_ioplug_t *io, snd_pcm_sframes_t *delayp)
snd_pcm_chmap_query_t **(* | query_chmaps )(snd_pcm_ioplug_t *io)
snd_pcm_chmap_t *(* | get_chmap )(snd_pcm_ioplug_t *io)
int(* | set_chmap )(snd_pcm_ioplug_t *io, const snd_pcm_chmap_t *map)

## Detailed Description

Callback table of ioplug

## Field Documentation

## ◆ close

int(* snd_pcm_ioplug_callback_t::close) (snd_pcm_ioplug_t *io)

close the PCM; optional

## ◆ delay

int(* snd_pcm_ioplug_callback_t::delay) (snd_pcm_ioplug_t *io, snd_pcm_sframes_t *delayp)

get the delay for the running PCM; optional; since v1.0.1

## ◆ drain

int(* snd_pcm_ioplug_callback_t::drain) (snd_pcm_ioplug_t *io)

drain; optional

## ◆ dump

void(* snd_pcm_ioplug_callback_t::dump) (snd_pcm_ioplug_t *io, snd_output_t *out)

dump; optional

## ◆ get_chmap

snd_pcm_chmap_t *(* snd_pcm_ioplug_callback_t::get_chmap) (snd_pcm_ioplug_t *io)

get the channel map; optional; since v1.0.2

## ◆ hw_free

int(* snd_pcm_ioplug_callback_t::hw_free) (snd_pcm_ioplug_t *io)

hw_free; optional

## ◆ hw_params

int(* snd_pcm_ioplug_callback_t::hw_params) (snd_pcm_ioplug_t *io, snd_pcm_hw_params_t *params)

hw_params; optional

## ◆ pause

int(* snd_pcm_ioplug_callback_t::pause) (snd_pcm_ioplug_t *io, int enable)

toggle pause; optional, called inside mutex lock

## ◆ pointer

snd_pcm_sframes_t(* snd_pcm_ioplug_callback_t::pointer) (snd_pcm_ioplug_t *io)

get the current DMA position; required, called inside mutex lock

Returns
  buffer position up to buffer_size or when SND_PCM_IOPLUG_FLAG_BOUNDARY_WA flag is set up to boundary or a negative error code for Xrun

## ◆ poll_descriptors

int(* snd_pcm_ioplug_callback_t::poll_descriptors) (snd_pcm_ioplug_t *io, struct pollfd *pfd, unsigned int space)

poll descriptors; optional

## ◆ poll_descriptors_count

int(* snd_pcm_ioplug_callback_t::poll_descriptors_count) (snd_pcm_ioplug_t *io)

poll descriptors count; optional

## ◆ poll_revents

int(* snd_pcm_ioplug_callback_t::poll_revents) (snd_pcm_ioplug_t *io, struct pollfd *pfd, unsigned int nfds, unsigned short *revents)

mangle poll events; optional

## ◆ prepare

int(* snd_pcm_ioplug_callback_t::prepare) (snd_pcm_ioplug_t *io)

prepare; optional

## ◆ query_chmaps

snd_pcm_chmap_query_t **(* snd_pcm_ioplug_callback_t::query_chmaps) (snd_pcm_ioplug_t *io)

query the channel maps; optional; since v1.0.2

## ◆ resume

int(* snd_pcm_ioplug_callback_t::resume) (snd_pcm_ioplug_t *io)

resume; optional

## ◆ set_chmap

int(* snd_pcm_ioplug_callback_t::set_chmap) (snd_pcm_ioplug_t *io, const snd_pcm_chmap_t *map)

set the channel map; optional; since v1.0.2

## ◆ start

int(* snd_pcm_ioplug_callback_t::start) (snd_pcm_ioplug_t *io)

start the PCM; required, called inside mutex lock

## ◆ stop

int(* snd_pcm_ioplug_callback_t::stop) (snd_pcm_ioplug_t *io)

stop the PCM; required, called inside mutex lock

## ◆ sw_params

int(* snd_pcm_ioplug_callback_t::sw_params) (snd_pcm_ioplug_t *io, snd_pcm_sw_params_t *params)

sw_params; optional

## ◆ transfer

snd_pcm_sframes_t(* snd_pcm_ioplug_callback_t::transfer) (snd_pcm_ioplug_t *io, const snd_pcm_channel_area_t *areas, snd_pcm_uframes_t offset, snd_pcm_uframes_t size)

transfer the data; optional, called inside mutex lock

The documentation for this struct was generated from the following file:

- /packaging/alsa-lib/include/pcm_ioplug.h